PTC Heating Element Shielding for Vehicle EMC Reduction
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Solution Overview
Problem
Electrical heating devices for motor vehicles often cause electromagnetic interference (EMC) issues, which are undesirable as they can lead to acoustic disturbances and other problems in vehicle interiors, such as radio interference.
Innovation Solution
A heat-generating element with a positioning frame made from non-conductive material, featuring multiple receptacles for PTC elements, contact plates with different polarities, and a sheet metal cover that forms a shield to reduce EMC interference. The sheet metal cover is isolated from contact elements and can be connected to the positioning frame via overmolding or injection molding, providing a complete shielding of the heat-generating element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat-generating element is used in an electric heating device, then heating function is achieved, but electromagnetic interference problems occur
Solution Approach 1:
The patent applies the shielding principle by introducing a conductive shield structure that converts the harmful electromagnetic radiation into a controlled electrical signal path. The shield captures electromagnetic interference and directs it to ground, transforming the harmful effect into a manageable electrical connection problem that is solved through proper grounding design.
Solution Approach 2:
The conductive shield acts as an intermediary element between the heat-generating element and the surrounding environment. It mediates the electromagnetic field by providing a controlled path for electromagnetic energy, preventing direct interference with other components while maintaining the heating function of the original element.
2Object-generated harmful factors
If a sheet metal cover is added to shield the heat-generating element, then electromagnetic interference is reduced, but device complexity increases
Solution Approach 1:
The conductive shield is designed to serve multiple functions simultaneously: it provides electromagnetic shielding, acts as a structural support element, and serves as an electrical connection path to ground. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving effective shielding.
Solution Approach 2:
The patent merges the shielding function with existing structural components of the heating device. Instead of adding a completely separate shielding system, the shield is integrated with the housing or support structures, combining mechanical support and electromagnetic shielding into a unified design that minimizes overall complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces EMC problems by creating a comprehensive shielding effect around the heat-generating element, minimizing electromagnetic interference and improving the operational stability of electrical heating devices in vehicles.
Implementation Method 1
the sheet metal cover forms a shield for the heat-generating element. Accordingly, an electrical heating device encompassing the heat-generating element causes reduced EMC problems
Implementation Method 2
This positioning frame is typically made of an electrically non-conductive material and forms at least one, usually several, receptacles for at least one PTC element
Data Source
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AI summary
The device has a layer structure (46) arranged in a frame (44) and comprising layers of waving ribs and heat generating elements. One of the heat generating elements include positive temperature co-efficient (PTC) elements, which are arranged between parallel contact plates. Waving rib elements are arranged one behind the other in a passage direction of medium e.g. water. The ribs are arranged transverse to the passage direction of the medium. A cooling body (32) is sealingly inserted into a connector housing, and a sealing element bridges a gap between the body and contours of the housing. An independent claim is also included for a frame.